Ramblings on giant scale radio control airplanes and helicopters

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Ok, I thought the season was over and wrote the preceding wrap-up. Its been unseasonably warm and I’ve been able to fly everything right up to New Years day. We finally got some snow though, so it will be mostly the helicopters. foamies, and Valiant on skis till spring. Looking forward to the 2nd Annual Boston Blizzard Fly In this year, if we have a blizzard. Hoping there is more than two of us like last year🙂 Here is a video if you missed it;

The last few weeks, I’ve been putting flight time on the Decathlon. The DA-150 has been running flawlessly now that I have solved the non-start issue due to the error in programming the ignition kill module. I’ve posted a video on YouTube of a few flights. Nothing fancy as they were mostly dynamic flight tuning flights and just getting used to what the airplane wants in a given maneuver.

I’m looking forward to next season with it, and will practice and pull together an aerobatic flight routine for it, mostly scale with some 3D thrown in for fun.

One thing I haven’t written about is the 50CC MXS-R that I picked up used as a BNF with a DLE55. After a few flights getting it trimmed and balanced out, it flys very well. Tons of reserve power, lightning fast roll rates and very responsive elevator and rudder. Very fun aircraft. Strangely enough, I don’t seem to have a photo of it on my hard drive. So instead, here is a shot of one of our members getting ready to start his monster bi-plane nick named Binky.

I Haven’t posted much this season. Mainly just too busy having fun and not really giving much thought to sitting in front of the computer and writing about it.

I had several issues that were plaguing me this season. It wasn’t smooth sailing like the last. The first was having multiple things failing on the Valiant. I flew it hard, so I guess some problems are expected. But still, there were also quality issues, mostly with regard to the factory glue materials or assembly process. I usually give very high marks to Hangar 9, but I feel they failed me with this ARF.

The first issue was the failure of the left aileron servo mounting structure. It basically just came unglued and the servo was dancing around within the wing while the aileron was left dangling by its hinges. I fixed it, added some reinforcements, and did the same for the right side as a preventative measure.

Next up were the flap servo mounting points. Same basic issue, same resolution. In hindsight I probably should have done these at the same time as the aileron servos. The next failure was both flap control horns that are mounted in the flap surface broke off even with the flap hinge surface.

Flap control horn, factory installed, broken on both flaps.

I’ll give Hangar 9 a break on this one, as I don’t think it was designed to be flown as hard as I have been, such as deploying full flaps at high speed while rolling inverted for a split-S with a hard pull at the bottom to setup for landing. Let’s just say I “exceeded the design limitations of the aircraft”. Put a check mark in my column on this one.

I was fighting with my Align 700 (E03) due to stripping the main gears flight after flight. What I now believe happened is that I stripped the main gear after a fast hard start and accidentally replaced it with a 110 tooth version rather than the 112 version to match the 12 tooth pinion. This is what caused the next 5 main gears to strip on their first flights. After checking everything, I finally realized the mismatch, replaced it with the correct one, and the problem went away.

Both Align 700s also broke their one way bearings and needed replacement. One (E04) just let go in the air, followed by a successful auto rotation. The second (E03) failed on start up by slipping and not providing enough power to lift off.

I had intermittent engine start issues with both the Decathlon and Yak54 which caused me to put them back into the trailer on several outings without ever taking flight. Frustrating. Sometimes they started and ran flawlessly,

Extreme Flight Yak54 with a DA50 at the Westport NY fly-in over July 4th weekend.

and others they did not. It took some time to track down the issue since it was intermittent, and seemingly without reason. The problem was always the optical kill module. At the field sometimes it just wouldn’t start, but nearly every time I got it into the shop to test it, the module was fine.

But at one point while troubleshooting I noticed that the Aux3 end point in the radio programming was different from the last time I checked. Trying to track this down, I finally found that one of the sliders on the back of the DX9, the ones nearly no one uses, was still active and mixed to the Aux3 channel that I was using for the optical kill module. I checked the YAK programming and it was the same issue. Evidently, when handing the radio I would offset the slider changing the mid-point for the optical kill module such that the kill switch wouldn’t reach into the activation range. The sliders are not on my pre-flight checks because I never use them for anything and they are not tied to any channel. Except they were in this case🙂

Luckily, no crashes or mishaps this season. Just some problems that plagued me for a while and always left me scratching my head.

Now the winter season starts. Valiant on skis, helis in the snow, and the Second Annual Boston Blizzard Fly-In if the weather allows!

Finally got the Valiant on the water, but not without some excitement! I ordered the scale float set for the 1/4 scale Hangar 9 Cub since they were a bolt on with little modification or building required. They were pricey, but they should look great on the airplane, and they are already built saving me a lot of time.

I was unhappy with the quality of the floats once I opened the box. I almost returned them, but decided to keep them anyway. When you look close, the lack of quality is apparent. But from a ‘stand off’ scale they look good.

Even with the heavy floats, the Valiant got up on step quickly and took off with authority. The DLE35RA motor and Valiant are a great combination. Lots of power, yet doesn’t feel heavy on the nose or overpowered. The DLE35RA has also been running flawlessly for the last 75 or so flights. Not even an hiccup. It ran just as well while it was installed in the BigFoot, so it probably has around 125 or so flights without any issues.

Although I did experience a nice blunder when I installed the floats. Pilot error, almost costing me the airplane. Having flown off water in the past, I knew I probably wouldn’t need to install both sets of water rudders that came with the float kit. So I only installed one side.

Being in a rush to get it ready for flying the next morning at a float plane fly in, I neglected to think about the ramifications of not installing the second water rudder. Thus there were two blind nuts installed for the mounting point that were left open. Egads!

After the successful maiden flight, it sat in the water waiting for its next flight. Having so much fun on the first, I took it up minutes later for another flight. I trimmed it out, did some loops, rolls, a couple spins, and even did a gentle snap roll. After landing, a buddy and I sat pond side admiring the plane, had lunch, sat and chatted som, and flew other airplanes.

Then it was time for flight three. This is when things got very interesting! During all our chatting about life, having lunch, etc, the left float was slowly filling with water. I started it up, taxied out, and took off and immediately knew I had a big problem. She pointed her nose nearly straight up and started yawing to the left toward the tree line. I corrected the yaw but needed to just let it climb and hope to clear the trees. Just as it stated to slow considerably due to the added weight of the water, I was able to push the nose over and sneak through a clearing at the top.

1/4 Scale Hangar 9 Cub floats.

My fun wasn’t over though! Now that I narrowly escaped hitting the tree tops and had it turned downwind and somewhat level, I got to do the moving CG dance. She went about 60 degrees nose down as the water sloshed to the tip of the float. I corrected back toward level, then she went 60 degrees nose up as the water sloshed to the back of the float. This continued with me struggling to achieve level flight.
After several cycles of this dance, I somehow managed to get the water level in the float stabilized and I was flying mostly level with small corrections. But I still had to point the nose down on final for the landing, and feared she would again start the dangerous dance. So I tried to keep the plane as level as I could, and use power to control the descent. It worked, and the landing was mostly uneventful. I think the water once stabilized was mostly held in place by the internal formers in the float.

We put the Valiant on the airplane stand, tilted it back at an extreme angle, and spent about 5 minutes watching the water dripping out of the left float. We guessed it was nearly two soda cans worth of pond water!

Yes, those blind nuts are now sealed tightly🙂

Image or our club Flying Field and pond.

The above image shows our club field and runway, as well as the pond just beyond the runway we use for flying float planes. The vantage point is on a raised observation platform at the runways midpoint. We share this runway with full scale airplanes and ultralights. Generally, there is only light full scale traffic most days we fly. The runway is about 2200′ in length, and the pond is roughly half that with a sandy beach at one end.

I wasn’t feeling excited about the Decathlon for some reason after flying it mid last season. I’m not sure why, nothing I could really put my finger on. I suspect that it has more to do with having a trailer slightly too small for it, dealing with the large wings and no wing bags to help manage them, and just the fun of dealing with a plane of that size.

With the thoughts of selling the airplane rather than buying a larger trailer, I decided to fly it and get some video and images for the ‘for sale’ listing. I also found a suitable and easy way to transport the wings in the SUV rather than the trailer which also made life easier.

Then I flew it. Six times that day. I fell back in love with it. It flies awesome, has a presence in the air that just screams full scale, and its built stable and reliable. Why would I get rid of it? Sure, a slightly smaller Decathlon that fit entirely in the trailer would be easier. But it would mean spending a lot of time on a new build, more cost, etc. So I decided to work the issues rather than replacing the airplane.

I finally found and ordered a suitable set of wing bags. That will allow protection when transporting, and allow me to throw those in the back of the SUV, or suspend them from the ceiling in the SUV or trailer. That will help greatly with the frustration of dealing with the wings. I rearranged quite a bit of the gear in the trailer to make getting the large fuselage in and out a lot easier. And using the SUV, which is always towing the trailer, as extended trailer space makes life easier as well. So now I have a good workable solution for transporting the Decathlon.

On to phase two. Getting the smoke system working correctly (bad check valve suspected), further dynamic flight testing, mixes, setting up a aero-tow hook for towing gliders with increased fuel and batteries.

Not willing to wait until the snow clears the runway for its maiden flight, I used a small 5’x10′ patch of visible grass on the runway and took to the air. Take off was uneventful needing only some up elevator trim to compensate for the nose weight added that morning after final balance check with full fuel on board. Elevator authority was more than adequate, as was rudder. Even while on high rates, I would have liked more aileron authority as the roll rate was slower than I am accustomed to. Granted, I am accustomed to flying aerobatic airplanes, so take that with a grain of salt.

Flight in general was very comfortable, its a very stable airplane in the air. Inverted flight also very stable with just a hint of down elevator, confirming the CG is just about right. Knife edge showed a lot of coupling, but as expected for a high wing airplane. Slow flight was a joy, again very stable, with stalls a relaxed wing ‘droop’ to either side. Not a drop, but it just kind of mushes along and slowing a wing droops to either side. A little power and back to stable flight.

With slow flight and about 20 degrees of flaps, the Valiant floats along nicely with just a touch of power. With about 45 degrees it provides a significant braking effect in a dive with power off, and with power applied allows for slow stable harrier passes where throttle is controlling altitude and elevator attitude.

Approach and landing was also uneventful. The approach was slow and stable. Had I managed to put it back on the 5’x10′ patch of grass showing landing would have been picture perfect. However, I was off a few feet and rolled off into the snow which acted as braked and nosed over the Valiant in to the soft snow with no damage.

All in all a very nice flying airplane. I’m going to have a lot of fun with this airplane!

I flew the Yak54 all last season as setup and purchased from the previous owner. There were a few things that I wanted to change, but it was perfectly flyable so I left it. I decided that this spring was the time to do the updates.

Since I’m using A123 batteries in my other airplanes, I wanted replace the aging Duralites and replace them with the A123’s as well. It would then match the same charging discipline as my other airplanes and not be an exception to the rule waiting for me to make a mistake. I’m also adding a second battery so the power system will be fully redundant. The current JR921 receiver using DSM2 will be replaced with a powersafe AR9110 using DSMX. Lastly, changing the fuel filter, resetting the failsafe to snap/spin, new carbon fiber landing gear with wheel pants, and cleaning up some of the wiring and eliminating a bunch of unnecessary connectors with custom length servo leads.

All in all it will be a bit more reliable, have better interference rejection with the DSMX receiver, and fully serviced and ready for the flying season.